A Year 12 student from Shepparton created this presentation for VCE Environmental Science: Unit 3 school assessed coursework.

1. VCE Environmental ScienceUnit 3: Energy and Greenhouse Gases Area of Study 1 SAC 1B: a comparison of a fossil fuel and a non-fossil energy source. By Lisa Down

2. Natural Gas vs. Geothermal Energy Natural gas is a fuel made up of several different hydrocarbon gases: methane, ethane, propane and butane. There are also other compounds like carbon dioxide, helium, hydrogen sulphide and nitrogen found in the mix. The carbon and hydrogen in Natural gas is formed by the decomposed remains of plants and animals that accumulate at the bottom of lakes and oceans. After millions of years of being buried beneath huge layers of other sediments, the high pressure of being buried and the heat of the earth’s core transforms the material into coal and natural gas. It is formed as pockets of gas over crude oil or inside porous rock formations. It is found all over the world in plentiful supply deep in reservoirs beneath the surface of the earth and under the ocean’s floor. Geothermal energy is the energy that comes from deep within the Earth, sometimes emerging as natural springs or geysers. It comes from several places: the earth’s core, movement of continental plates and decaying of naturally occurring substances within the crust. It it always there, but it is not always accessible. Volcanoes, hot springs and steam vents are the easiest places to access geothermal energy. There are four types of geothermal energy so it depends on what type it is as to how accessible it is, though the general idea is that it isn’t very accessible as most of it is deep beneath the surface of the earth and drilling for it is expensive. The four types are: hydrothermal, geopressured, hot dry rock and magma.

3. Extraction Once a team of drilling experts has determined a possible natural gas deposit the drilling begins. They install a development well which channels the gas out of the reservoir and into collection tanks. The land used in extracting gas reservoirs depends on how big the deposit is estimated to be. Geothermal energy comes from various locations and sources so different techniques have to be used. Drilling for geothermal energy is as expensive as drilling for gas so recycling “dry” oil or gas wells is a cost-conservative method used to reach the geothermal reservoirs. Plants are another way of extracting the energy. There are three types of plants used: dry steam, flash steam and Binary power. Hydrothermal energy is the only really viable geothermal source as it is the only one fairly accessible. The water and steam are drawn out through a hole drilled into the earth’s crust and carried in pipes to a geothermal plant. The steam and water are separated and, after going through several conversions, is either channeled off or store away.

4. Transport Natural gas is transported via a network of various pipelines, depending on where the gas is supposed to end up. There are three main types of pipeline used in this process. The gathering system, transporting the raw material from the wellhead to the processing plant, is the most vital pipeline. The interstate/intrastate and the distribution systems are the pipelines used to funnel the processed product to various areas for use. This method of transport is the only safe way the odorless substance can he moved from the reservoir. In some cases, geothermal energy cannot be moved so it has to be sent straight through as electricity to power close-by houses. This is not a very efficient method as it only powers nearby places. The energy can be stored but unless it can be used, it is basically useless.

5. Use The main use of natural gas is as a source of heat one way or another in industrial, commercial and residential settings. Used to warm the house, cook food, dry clothes, produce electricity, power turbines, steam-boilers and, more recently, micro-turbines. During a 2007-2008 report, natural gas accounted for 19% of Australia’s energy. While natural gas is responsible for heat, geothermal energy is used to supply power or electricity to nearby places. It is very good at powering up the electrical needs of those close to the source but, unlike gas, it is not so good at powering places far away from the source of the energy as the transport methods are not very efficient.

6. Economic Impacts Both natural gas and geothermal energy are fairly cost-conservative. Appliances that use natural gas are virtually maintenance free. It is also a world-wide resource. Geothermal plants being as small as they are, are not very costly. Unfortunately, the combined cost of drilling, installing pipes and leasing the land needed is a rather large sum and when they first begin, there is no guarantee there will be enough gas for a worthwhile well. The same can be said for geothermal energy, neither source can be particularly reliable. Geothermal sites, for instance, can suddenly stop producing steam for no apparent reason.

7. Social Impacts A social advantage of both natural gas and geothermal energy production is the increase in local employment. Another advantage of geothermal energy is the amount of space the plants take up compared to the gas plants. Geothermal plants are relatively small so as to take up as little space as possible while gas plants are fairly large, depending on the size of the gas deposit. A serious disadvantage of gas drilling however, is that the sites of some of these wells falls on traditionally sacred sites for some cultures. A disadvantage of geothermal energy is the hazardous gases and minerals released when harvesting the steam, making living close to a geothermal plant risky.

8. Environmental Impacts Natural Gas is the cleanest of the fossil fuels, emitting fewer toxic chemicals and contributing less to the enhanced greenhouse effect. However, though the product is cleaner, the act of getting it it another story. The process can be damaging to the environment because a lot of the gas is located in fairly untouched natural places or under the ocean. Like natural gas, geothermal energy releases few air emissions into the atmosphere. It is also virtually noiseless, and are designed to blend into their surroundings. However, the extraction of geothermal steam and water can have an affect on the local habitat, draining away the nutrients the local plant life need to survive. It can also (over decades) cause subsidence or possible sinking of the land as the pressure in the geothermal reservoir decreases. Over 30 years, the amount of land used for a geothermal plant is 404 square meters of land per giggawatt hour compared to coal which is 3632 square meters of land per gigga watt hour.

9. Contribution to the Greenhouse Effect Geothermal energy produces little or no greenhouse gases, as it is heat energy from the earth’s core, therefore it does not contribute to the greenhouse effect. Natural Gas produces carbon dioxide and nitrous oxides. It in itself is sometimes considered a greenhouse gas as methane is a dangerous greenhouse gas and a major part of natural gas is methane. But the emissions that natural gas produces as it burns are drastically smaller than that of coal and oil. Coal’s greenhouse emissions are 90% in energy production.

10. International Agreements The Kyoto Protocol is an international agreement designed to stop carbon dioxide emissions. It began in Kyoto Japan on the 11th of December, 1997 but wasn't entered into force until February 2005 The Bali Action Plan is designed to take over from the Kyoto agreement in 2012. It did not introduce binding commitments to reduce greenhouse gas emissions but included the request for developed countries to contribute to the mitigation of global warming in the context of sustainable development. In addition, the Bali Action Plan envisaged enhanced actions on adaptation, technology development and on the provision financial resources, as well as measures against deforestation. Copenhagen accord "recognises" the scientific case for keeping temperature rises to no more than 2C but does not contain commitments to emissions reductions to achieve that goal. Bangkok conference commences this month and although not entirely confident, the UN is hopeful of some future policy for ongoing commitment to environmental research and funding to ensure reduction in greenhouse emissions.

11. National Strategies The Australian National Greenhouse Strategy is based on the Kyoto Agreement and is due for an overhaul this year. Much discussion and debate is currently being held at the moment about the future of our strategy including Coal tax or emission trading scheme. Future research into Greenhouse effects are considered to be of major importance.

12. State Policies In July 2010, the Victorian Government released the “Climate Change White Paper”, detailing the climate change policy. The White Paper outlined ten key policies: legislating to cut Victoria’s greenhouse pollution; moving towards a cleaner energy future; making Victoria the "solar State”; supporting cleaner and more efficient homes; positioning Victoria to be a global leader in clean technology; creating new opportunities in agriculture, food and forestry; delivering innovative transport solutions; greening government; helping Victorians adapt to climate change; and strengthening our climate communities.

13. Local Strategies The City of Greater Shepparton has a Local Environmental Sustainability Priority Statement. This covers reducing greenhouse emissions but does not have a direction on how to do this. It concentrates strongly on waste management instead of greenhouse gases.

14. Bibliography Issues of Sustainability workbook www.unctad.org/infocomm/anglais/gas/sitemap.htm www.naturalgas.org/www.bydesign.com/fossilfuels/links/.../natural_gas/gas_get.html www.ehow.com www.extension.psu.edu www.oru.com/energyandsafety/naturalgas/benefits www.buzzle.com/.../advantages-and-disadvantages-of-natural-gas www.coloradocollege.edu/dept/an/.../topics/Social%20Impacts www.lowimpactliving.com www.renewableenergydev.com/red/geothermal-energy/ www.library.thinkquest.org/06aug/02365/geothermal. www.web.worldbank.org www.clean-energy-ideas.com www.associatedcontent.com www.geo-energy.org/reports/Environmental%20Guide.pdf www.global-greenhouse-warming.com www.blakedawson.com www.dpi.vic.gov.au